For a permanent magnet,which of the following properties is essentially required?

Curie temperature is the temperature above which

Suppose a small cylinder of a paramagnetic substance and a small cylinder of a diamagnetic substance are placed between the (parallel) pole pieces of a strong magnet,so that they are aligned along the direction of the field lines. Will they attract or repel each other?

What type of materials can be used to make an electromagnet?

$A$ sample of a paramagnetic salt containing $3 \times 10^{24}$ atomic dipoles each of dipole moment $2 \times 10^{-23} \text{ A-m}^2$ is subjected to a uniform magnetic field of $880 \text{ mT}$ and cooled to a temperature of $3.5 \text{ K}$. The degree of magnetic saturation achieved is $10 \%$. If the sample is subjected to a magnetic field of $990 \text{ mT}$ and cooled to a temperature of $2.1 \text{ K}$, then the total dipole moment of the sample is (in $\text{ A-m}^2$)

If $\chi$ stands for the magnetic susceptibility of a substance, $\mu$ for its magnetic permeability, and $\mu_0$ for the permeability of free space, then which of the following is correct?